1. Start by cooking the leek in the oil over medium-low heat until soft but not colored. Add a bit of water to prevent coloration if needed.
2. Take about 1/3 of the leek mixture and transfer to a bowl with the meat, soy sauce, egg, parmesan, salt and pepper. Mix well with your clean hands to combine. At this point, the meat mixture will be kind of wet. Let it sit for about 10 minutes in the refrigerator.
3. Form the meatballs and make them a bit smaller than a golf ball. In a non-stick skillet, cook them in a bit of olive oil over medium heat, turning frequently, until brown all over.
4. Transfer the meatballs to the other pan containing the leeks, add the wine and the broth, cover and cook over medium-low heat for about 20 minutes.
5. Add the cornstarch mixed with water to thicken the sauce and the parsley, check seasonings and serve hot with a side of vegetables and brown rice.

I am sure that the sweetness from the leeks makes this dish just gorgeous. Actually i like this leek idea very much as it has so many potentials for other dishes as well. Thanks for the inspiration. What a beautiful meal.